My research lab uses fluorescence imaging technology combined with electrophysiological measurements to study problems with the transmission of information in the brain. Such problems are the foundation of numerous brain disorders including schizophrenia, depression and Parkinson's disease. We need a thorough understanding of the brain's communication process to understand and develop treatments for these disorders. Brain function depends on the activity of neuronal circuits, which are formed by thousands or millions of neurons (nerve cells) that communicate with each other at points of contact called synapses. Neurons communicate when the pre-synaptic neuron releases a chemical transmitter that diffuses across the synaptic space and binds to receptors on the post-synaptic (receiving) neuron. The receptors are often located on branches of the neuron called dendrites. My research examines the factors that control the amount of chemical transmitter released, and in particular, the regulation of release by calcium ions in pre-synaptic neurons. Transmitter release is stimulated by an influx of calcium into the pre-synaptic neuron. Calcium influx is controlled by changes in the electrical potential of the pre-synaptic neuron that regulate the opening and closing of the voltage sensitive ""gates"" of calcium permeable pores in the neuron's surface. By changing calcium influx and accumulation in neurons, the strength of the synaptic connection can be varied to adapt to new conditions or tasks. Using fluorescent dyes that are sensitive to calcium, we monitor calcium in pre-synaptic neurons at the same time that we measure synaptic transmission electrically. Our laboratory has the unique capability to make these measurements in an intact living mammalian brain. We are investigating how activity in the pre-synaptic neuron and substances such as dopamine or serotonin control transmitter release by their effects on calcium, and the biochemical machinery that release transmitter in response to calcium. We also are studying how the signal reception at the post-synaptic neuron is regulated by electrical properties of the dendrites.